Amorphous SiO2 based cathode material and preparation method and application thereof

Abstract

The invention discloses an amorphous SiO2 based cathode material and a preparation method and application thereof. The amorphous SiO2 based cathode material SiO2 is mixed with PVDF, the purity of SiO2 is analytically pure, and the particle size of the SiO2 is 5-10 micron order. The preparation method comprises the following steps: putting weighed powder into a mold, preparing the powder into wafers 1-1000mm in diameter and 1-1000mm in thickness under 10-1000 MPa; and sintering under 500-1500 DEG C for 1-100h to prepare the cathode material. The preparation method using the amorphous SiO2 as the cathode material makes use of the isotropic characteristic of the amorphous material without preferred orientation, a fused salt electrolyte does not have preferential infiltration lanes, so that the electrolytic reduction speeds in all directions approach unity, and finally extra fine nanoscale Si particles are directly obtained.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, in particular to an amorphous SiO 2 Cathode materials and their preparation methods and applications. Background technique [0002] At present, nano-scale Si is the best anode material for new lithium-ion batteries, and its lithium storage capacity is about 10 times higher than that of traditional graphite anodes. However, the traditional carbothermal reduction method can only prepare bulk Si because the temperature is higher than the melting point of Si. CVD, PVD, PLD and HF corrosion methods are commonly used in the laboratory to prepare nano-scale Si materials, with low yield and high cost. Molten-salt electrolysis can form crystalline SiO below the melting point of silicon 2 The direct reduction of nano-scale Si has low economic cost and simple equipment. Crystalline SiO during electrolysis 2 There is a preferred direction of conduction, molten salt electrolyte (usually CaCl...

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Problems solved by technology

[0003] The object of the present invention is to provide a kind of SiO based on amorphous state 2 The cathode material and its preparation method and application are aimed at solving the problem of low yield and high cost in the traditional carbothermal reduction method; the rod-shaped or fibrous nano-Si obtained by the molten salt electrolysis method is not suitable for the paste assembly of the negative electrode of the battery question

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